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Non-Swaged Cartridge Heaters

Non-swaged cartridge heaters offer a cost effective solution where the performance of a swaged cartridge heater is not required. Non-swaged cartridge heaters can be used at watt densities up to 45 watts per square inch and temperatures up to 1000°F. Non-swaged cartridge heaters offer tighter length tolerances than swaged heaters and can be built with 3 independent heat zones. Non-swaged heaters are not recommended for applications where there is a lot of vibration or impact.

  • Standard leads are UL rated to 550°C (1022°F) and are connected internally with nickel connectors.
  • High temperature cement filling protects leads and internal parts. Epoxy and silicone rubber leads are available.
  • Nickel-Chromium resistance wire stretched evenly throughout the length for even heat distribution.
  • High purity MgO is vibratory filled into the heater for maximum heat transfer.
  • 304 Stainless Steel sheath for superior oxidation resistance.
  • Welded end disc to prevent contamination and moisture absorption.
Nominal DiameterMinimum DiameterMaximum DiameterStd. Lead Wire GaugeMax Amps with Std. Lead WireMax Lead Wire GaugeMaximum AmpsMaximum Volts

Non-swaged heaters offer tighter length tolerances than swaged heaters, making them ideal for applications such as platens where heaters are generally longer. Non-swaged heaters are not recommended for applications where there is is a lot of vibration or impact.


Most of the lead configurations and options available for swaged HotRod heaters are also available for non-swaged cartridge heaters. Our standard options are listed below. If you don’t see what you need, consult your MPI Morheat agent for more information or contact us at  



Non-swag heater with flange
  • Standard flange material is stainless steel.
  • Flanges can be welded on the lead end of the heater.
  • Flanges can be used to hold a heater in place to prevent backing out during operation.
  • Flanges also assist in heater removal. 
  • Flanges can be round or irregularly shaped and are 1/16″ thick. 
  • Custom round or rectangular flanges available.
  • Contact Backer Marathon for standard and non-standard flange configurations at

Standard Flange Dimensions

Flange Outside Diameter1″1-1/2″2″
Can be used on5/16, 3/8, 1/25/16, 3/8, 1/2, 5/8, 3/4 1/2, 5/8, 3/4, 1
Hole Spacing3/41-1/181-1/2
Hole Size.14.16.20

Single Ended NPT Fittings

Non-Swag Single-Ended Group  

Single End NPT Fitting Specification Chart

Heater Diameter3/8″1/2″5/8″3/4″1″
NPT Thread Size1/43/81/23/41
Brass “A”.
Brass “B”.56.69.871.061.44
Stainless Steel “A”.
Stainless Steel “B”.56.67.871.061.37

Double Ended NPT Fittings

Non-Swag Double-Ended Group 

Double Ended NPT Fitting Specification Chart

Heater Diameter3/8″1/2″5/8″3/4″1″
NPT Thread Size1/43/81/23/41
Brass “A”
Brass “B”.56.69.871.061.37
Stainless Steel “A”
Stainless Steel “B”.56.68.871.06CALL

Mechanical Stops

Non-Swag Heater with Tab Stops

Mechanical Stops are ideal for preventing heaters from sliding too far into the hole. Backer Marathon offers the following mechanical stops:

  • Weld Beads
  • Tab Stops 
  • Locating Rings

Custom Fittings

Non-Swag Heater with Stainless Steel NPT Straight Threads
  • Straight Threads
  • Brass Cubes
  • Stainless Steel Cubes
  • Others to Your Specifications
End Seal Options

End Seals

CementProvides protection against some thicker liquids and dust, however it is not waterproof. It is also somewhat brittle and subject to cracking in high impact or high vibration applications. Up to 2600°F. 
Epoxy PottingProvides a very good seal with excellent mechanical strength. However, it’s adherence to Teflon or silicone rubber lead wire is only fair. It is rated up to 265°F and bonds well to Duraflex lead wire.
Epoxylite PottingProvides similar mechanical properties as epoxy potting. Up to 600°F. 
  • RTV Potting, when used in combination with silicone rubber insulated lead wire, provides the best seal of all options.
  • The down side to silicone is that it is limited to 500ºF and while extremely flexible, it is not as strong mechanically as other options.
  • Although the RTV is rated for 500ºF, silicone rubber leads are only rated to 392ºF. An option is to use Duraflex lead wire instead. Duraflex is rated to 1000ºF and has a heavy silicone coating.
  • While Duraflex is not sold as a waterproof wire, it performs very well in wet environments.
  • Another option is to use crimped on leads, then the power pins are sealed where they enter the heater and the type of lead wire does not matter.


 End Seal TypeMax TempMoisture ProtectionContaminationMechanical StrengthVibration ResistanceMoisture ApplicationsVibration or Flexing
Cement Potting2600°FPoorFairGoodPoorPoorPoor
Non-swaged heater with epoxylite pottingEpoxylite Potting600°FFairVery Good Very GoodExcellentGoodExcellent
Non-swaged heater with RTV pottingRTV w/ Silicone Rubber Leads392°FExcellentExcellentFairGoodExcellentAverage
Non-swaged heater with epoxy pottingEpoxy Potting265°FGoodGoodExcellentExcellentGoodGood
Other Options

Distributed Wattage

  • Distributed wattage heaters are often used in platens and sealing bars. Wattage is usually increased on the ends of the heater to compensate for end losses and maintain a constant temperature along the heated product.
  • Specify desired lengths in inches and wattages in percentage. 

Dual Voltage

  • Dual Voltage cartridge heaters can be engineered to operate at different voltage ratings. To order, specify dual voltage and voltage requirements. 


  • Individually controlled heat zones give flexibility when needing to control the heat along the length of a cartridge heater. These zones are commonly used in platen applications where tight temperature tolerances are important.
  • Three Zone heaters are constructed with (6) color coded leads. Yellow leads indicate disk end zone. Black leads indicate center zone. Red leads indicate lead end zone. Please consult factory for available diameters. Specify length and wattages of desired zones.
  • Dual Zone heaters are commonly constructed with 4 power leads.

Three Phase

  • MPI Morheat Cartridge Heaters are available for three phase delta for high amperage applications. Certain restrictions apply.
Watt Density


Watt density is calculated with the following formula: 

Watt Density = Wattage / Heated Length x Diameter x 3.14


Clearance is determined by taking the hole diameter and subtracting the heater diameter.

  • Cycling reduces heater life and high cycling applications should use lower numbers.
  • Staying below these values will result in increased heater life.

Max Watt Density

Hole Clearance1000*800*600*400*200*